The proposed project will investigate the overeating and obesity-inducing effects of high carbohydrate diets in laboratory rats. In particular, this project will follow-up the recent discovery that sugars are not unique in their obesity promoting effect since rats will overeat and gain excessive weight when fed polysaccharide solutions. The specific aims of this project are to clarify ghe role and importance of (a) carbohydrate taste, physical state (liquid vs. solid), and cost, (b) gastric factors, intestinal absorption rate, and the vagus nerve, (c) dietary micro- and macronutrient balance, (d) sex differences and brown adipose tissue in carbohydrate appetite and carbohydrate-induced obesity. The object of this research is to further our understanding of the role of dietary factors, carbohydrates in particular, in the regulation of caloric intake and body weight, and the etiology of obesity. This research, which involves the fields of psychobiology and nutrition, will provide new information on the potential health consequences of diets high in sugar and polysaccharides.